| Loess Plateau is the important dry farming area of North China,also the most serious soil erosion areas in China. Resulting in land degradation,increased production costs,the ecological environment further deterioration and lead to soil erosion for turning too times on top soil of traditional farming methods. By changing the cropping pattern to change agricultural ecological environment,reduce soil erosion caused by agricultural production,improve the productivity of dryland agriculture and water efficient use,and enhance upland soil erosion on the adverse environmental effects of the external resistance. In order to discover implementation model of Spring maize conservation tillage technology in the Loess Plateau,for the establishment of spring maize conservation tillage in Loess Plateau and provide theoretical basis for choose a reasonable way of farming. 2006-2010,this research continuous positioning,through field experiments to understand the whole set of agricultural machinery and agricultural operations such as weed control under conservation tillage techniques,set 3 of easy-tillage on seed production of conservation tillage (NT),conventional tillage + straw ( TS) and conventional tillage (CT). In order to discover the effects of conservation tillage of spring maize on soil environment and biological in Loess Plateau,cropping patterns by studying the effects of different growth stages of spring maize in soil water moisture and storage,dynamic of nutrients,changes in soil physical properties,soil properties and agricultural micro-environment changes of biological effects,the main conclusions are as follows:(1)5-years continuous experiment showed that compared with conventional tillage,conservation tillage improves the loess plateau phase 0-200cm soil moisture of spring corn fields (before sowing,jointing and flare opening),maize soil water storage higher than conventional tillage and conventional tillage + straw treatment during the whole growth significantly , compared with conventional tillage on soil water storage above the 43.66-96.71mm.(2)Compared with conventional tillage,conservation tillage significantly reduced the soil bulk density in jointing stage,flare opening and milk stage of maize,a decrease of 10%. Soil temperatures are the single peak under different soil depth and different tillage patterns, the daily maximum of soil temperature occurred at 14:00-16:00. Compared with conventional tillage,the temperatures of conservation tillage treatments higher than the average 7.02℃and 14.7℃,below the surface 5cm and 10cm after spring maize sowing,the jointing stage and flare opening on the ground below 5cm higher than 5.3℃and 2.6℃,compared with conventional tillage on soil temperature,and higher than conventional tillage 2.09℃in milk stage at 0-25cm average temperature. Composition and distribution of aggregates of conservation tillage treatments was significantly better than conventional tillage at 0-30 cm soil depth,no tillage + straw treatments,and particle size > 0.25 mm and diameter> 2 mm of the mechanical stability of the aggregates and water stable aggregates was the highest percentage at 0-10,10-20 and 20-30 cm soil layer,conservation tillage and conventional tillage + straw treatment are significantly different (P <0.05 ) with conventional tillage treatments,conservation tillage can significantly increase soil aggregate MWD values.(3)Soil organic matter content was significantly higher than conventional tillage,increasing the range of between 14.81% -38.37% on spring maize growth stages of plow layer (0-20cm) ; conservation tillage increased soil available phosphorus content,of flare opening at 0-40cm depth,than conventional tillage increase of up to 90.94%,and soil available phosphorus content of conservation tillage was significantly higher than the other two treatments after maize harvest at 0-20cm,compared with conventional tillage representing an increase of 10.27%; conservation tillage maize significantly increased soil available K content in milk stage,and soil available K content increased significantly of conventional tillage + straw treatment at before sowing,the jointing stage,flare opening and after-harvest of spring maize compared with conventional tillage at 0 -20cm; conservation tillage increased soil nitrogen content of jointing stage,flare opening,milky stage,after-harvest an increase of 11.05% -24.05% at 0-20cm.(4)Compared with conventional tillage,conservation tillage and conventional tillage + straw treatments increased the role of soil enzyme activities significantly,in the whole growth stages of spring maize,and soil urease activities of conservation tillage was significantly traditional farming and traditional tillage + straw at 0-20cm; Conservation Tillage significantly increased corn jointing stage and milky stage soil invertase activities of 0-20cm; conservation tillage improved soil phosphatase activities before sowing,jointing stage,milky stage and after-harvest spring of maize at 0-20cm; and reached the difference of treatment (P <0.05) level; conservation tillage treatments increased soil catalase activities significantly from before sowing to milk stage,and was significantly higher than conventional tillage; and can significantly increase soil catalase activities of flare opening and milk large of spring maize at 20-40cm. Soil microbial biomass carbon of conservation tillage was the highest before sowing of spring maize in the surface of 0-5cm,compared with conventional tillage higher than 54.92%; and soil microbial biomass carbon content of 0-5cm , 5-10cm after-harvest compared with traditional tillage and conventional tillage + straw highest increase of 20.99% and 51.80% respectively. Soil Microbial Biomass N content of before maize sowing at 0-5cm and 5-10cm,conservation tillage higher than conventional tillage and conventional tillage + straw,compared with before sowing of spring maize,soil microbial biomass nitrogen in each treatment,were more than 20% in the sub-soil of each treatment,the maximum reduction of 40.15%.(5)Compared with conventional tillage,conservation tillage have more secondary root number,plant height,stem diameter,ear leaf area and farmland values biomass accumulation in the key stages of spring maize,In the growth stages of spring maize BJG of conservation tillage treatments are the highest,and conservation tillage + crop protection of prevention of Tillage and plant protection measures have big effects on the spring corn protective ear length,kernels per row,grain number and yield components of grain weight and other indicators of a greater impact,ear length was significant difference for BJG and CC to deal with BO and CO,and conservation tillage treatments reached a significant level(P <0.01 ) differences between grain number and grain weight. Significant increase the yield of conservation tillage,the average maize yield per plant and field production rate were as high as 25.31%,compared with the extent of BO and CO,BJG handling field of spring maize per plant yield reached 36.17% and 41.48%. |
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